Well, for starters, they're not made of ink printed on paper, they're people.

Founded in Denmark in 2000, the Human Library movement features volunteers who agree to be "read" by others. In other words, they share their life experiences via one-on-one conversations, the goal being to foster greater understanding among people of different backgrounds and spark discussion of difficult subjects.

The project's Chicago chapter currently has eight participants, ranging from a brain tumor survivor to an Iranian feminist.

Casey is volunteering as the book "transgender male."

"I hope that by bringing these issues into open conversation we can promote acceptance and safety in our communities and work towards breaking down the barriers transgender people face," he said.

Ashley is volunteering as "biracial."

"With all of the race mixing going on in the U.S., it’s important to talk about cultural identity and the hardships of 'fitting in' with one culture or the other," she said.